Apparatus for producing photographic records



May 20, 1930. T. w. CASE 1359,434

APPARATUS FOR PRODUCING PHOTOGRAPHIC RECORDS Filed March 4, 1927 0 I/vnr/vroR Patented 'May 20, 1930 UNITED. STATES PATENT-OFFICE THEODORE wrrnmn'cesn, or AUBURNpNEW- YORK, Assrenon 170 east, nnsnancn LABORATORY 1110., or AUBURN, NEW. YORK, 'acoarom'rron on NEW YORK I nrram'rns IOIt- 'rnonucme "PHOTOGRAPHICY anconns A pplication filed March 4, 1927. Serial 1q'o.172,911.

This invention relates to certain new and useful improvements in apparatus for pro- .ducing a photographic record of light wave variations corresponding to-sound wave vasfiations. p

The invention. resides more specifically in the construction, form, size and operation ofthe light. source which is varied by variations in an electrical current corresponding to sound waves. One of the objects production of a light source of high intensity, the electrodes of which are in such a position that sputtering cannot dirty the wall of that A further object resides in the provision of a light source including a. bulb and suitable electrodes therein, inwhich the bulb includes a small capillary adapted to be photographed from the side rather than from the end.

Other objects and advantages relate'to the details of the structure and the form and relation of the parts thereof, all as will more fully appear from the following description taken in connection with theaccompanying drawings, in which The figure is a diagrammatic illustration of an embodiment of the invention.

The apparatus as illustrated comprises a bulb 1 of glass or other suitable material and comprising two chambers 2 and 3 lined substantially side by side and .connected together at one end of each chamber by a transversely extending small diameter tion that the moving film is subjected to the.

light rays emanating from the side of the capillary or tube of the invention is the The: slit. -5- may vary somewhat in length, but a slit 01%.1' of an inch in length is satisfactory for my purposev The bulb 1 contains an, ionizable gas, preferably helium under desired pressure. An electrode 7 in the form of a filament is positioned in'the chamber 3 and is adapted to be heated in any suitable manner, as by a cir- {cuit containing a source- 'ofpotential -8.

The other chamber 2- contains an unheated electrode -9- connected in circuit with the electrode or cathode -.7, said circuit containing a source of potential 10 and preferably a resistance 11--, and where amplification is desired, the secondary -12 of a transformer, the primary. 13 of which may be connected through any number of stages of amplification with ameans for varying current flowing in the circuits, as for instance the microphone .1-'-, the microphone circuit including a source of potential with battery 15.

The electrodes enclosed in the respective chambers are in such a position that sputterin'g will not darken the portion of the capillary -4- used for photographic purposes, and the electrodes as shown may partially underlie the inner wall of the respective chambers and to any extent desired.

The electrode -.7% constituting the cathode, has a coating comprising an alkaline earth metal, preferably barium oxide, whereby electron emission can be obtained without much light from the electrode. As stated','the photographic film moves past the side of the capillary l. rather than the end of the same which perinits the capillary to be supported very close to the slit such for instance, that it can, be enclosed in a tube an inch and a quarter in diameter.

The length of the capillary 4- should not exceed one-half an inch, and'preferably is not longer than one-fifth of an inch, and the nearer the length of the capillary approaches thelength of the slit, the more nearly perpendicular to the film will be the rays of lightemanating from the capillary.

The diameter of the capillary is preferably be'used in its place, the main distinction being that by the use of a heatable cathode considerably less voltage is required for operatmg'the device and low voltage telephonic cur-' rents are more readily and easily modulated.

The resistance of 't-hesmall diameter capillary or tube 4 is so great as to result in an extremely intense concentrated'glow in the capillary.

The figure of the drawings i's-of ad'iagrammatic nature and the film ..7- is indicated as moving lengthwise I of the capillary, whereas in operation it would preferably move crosswise of the capillary at substantially right angles to the direction indicated in the drawings. w

'Altho I have shown and described specific structures together with particularform and relation'of the parts, I do not desire to restrict myself to. the details of form'orrela- 'tion of the parts except where the same are specifically included in the claims heretoappended.

I claim:

1. A lamp for producing a photographic record of li ht wave variations corresponding to soun wave variations comprising a bulb formed in two chambers which lie side by side and a capillary connecting the two mbers on a line lying outside the limits thereof, an electrode in each chamber,- and a circuit connecting the electrodes.

2. A lamp for producing a photographic record of light wave variations corresponding to soundrwave variations comprising a bulb formed in two chambers and a tube of a diameter not greater than one-eighth of an inch extending transversely of and connecting the two chambers on a line lying outside the limits of the chambers.

3. A lamp for producing a photographic record of light wave variations correspondside, a tube having ing to sound wave variations comprising a bulb formed in two chambers lying side by a 'diametertnot substantially greater than one-eighth of an inch extending transversely of and connecting said chambers on a line lying outside the limits of the chambers, an electrode in each of said' chambers and so positioned that sputtering will not dirty the effective portion of the wall of said tube, and a circuit connecting said electrodes.

4. A lamp for producing a photographic record of light wave variations corres ond ing to sound wave-variations comprising a bulb formed in two chambers and a tube connecting the chambers on a line lying outing to sound wave variationscomprisin bulb formed in two chambers which lie s1de .side the limits of the chambers, said tube 5. A lamp for producing a photographic record of light wave variatlons corresponding'to sound wave variations COIHPI'lSlIlg a bulb formed in two chambersand a tube connecting the chambers on a line lying outside the limits of the chambers, said tube being of a diameter not substantially greater \than 1/32nd of an inch, an electrode in each chamber, a circuit connecting the electrodes, and means for heating onlof the electrodes.

61 A lamp for'producing'a photographic record of light wave variations correspondby side and a capillary extending transversely of and connecting the twochambers on a line lying outside the limits of the chambers, an electrode in each chamber, the .icathode of said electrodes comprising an'alkaline. earth metal, and a circuit connecting the electrodes.

In witness whereof 1 have hereunto set my hand this 22nd day of February, 1927.

THEODORE WILLARD CASE. 

